Thread: Idea for Carbatec 2.75HP DC Modification / Ducting Layout for Feedback

I also put all machine use on hold to stop and sort out the DE situation once and for all. Problem was, that was in 2020 and I'm still not there yet (almost)!

As to the impellor size, trying to measure it (or approximate) by the outer blower dimensions is difficult because the blower radius increases in a spiral as it expands from being nearest to the impeller (with some gap) to the widest at the outlet width (most gap). A 14inch (~355+mm) impeller would most likely need longer than that 410mm measurement.

I'm not sure about sucking up metal, would worry about hot bits mixing with timber dust, or if the metal might abrade the impeller or internals over time?

Based on the dimensions of the housing, I’d say that’s a 12” impeller. I think they increase the depth of the blades for the 3HP unit.

Originally Posted by Kristen

While we're talking shop, what's the deal with sucking up metal shavings?
I drill steel with cutting compound a bit, and I dry cut brass and aluminium from time to time on my saws.
My intuition is that the aluminium and brass would be OK, but the steel swarf mixed with cutting compound might be a a no goer.

I regularly suck up steel swarf/dust and cutting/coolant with my DC.
This is OK provided the swarf doesn't get red hot.
The most damage that has occurred to the impeller and housing in 12 years is it's missing a bit of paint.

A tricky task is grinding steel - not because of the sparks as the big air flow rapidly cools them down so within the first meter of ducting***.
The problem is a hot workpiece, if a red hot or near red hot piece ends up in the dust bin containing wood dust that can start a fire. This is the most common cause of fires in DCs.
To get around this I put a steel hot object catcher inline between the grinder and flexy connection to the ducting.

The shiny flex is het resistan aluminised mylar.
The 20L drum I scored from a skip at work
IMG_1615.jpg

Here it is in use on a home made variable speed thin kerf cutting saw.
70+% of the grit/duct is captured by a baked bean can directly under the disc, its possible to see it just under my right hand
bestofthebest.jpg

The following is a major gotcha.
At no time should flexy that has been used for wood dust and not been cleaned be used close where sparks could arise.This is what happened to a mate of mines flexy when he hit some nails with his 14" panel saw. You can still see the residual sawdust inside the flexy.
A spark/metal dust catcher will get around this.
Fire3.jpg

That's some quality information.
Cheers Bob.

Your ducted catch can set up is a rad idea.
Like a mini cyclone.

The image of the burnt out duct is pretty frightening.

I've seen a few videos of cats cutting straight through gal brads and it causing no harm to the table saw blade.
I'll be giving that a miss I reckon.


And cheers to everyone here.

This forum is great.

Originally Posted by Kristen

That's some quality information.
Cheers Bob.

Your ducted catch can set up is a rad idea.
Like a mini cyclone.
.

RE: metal catcher
It's not my idea, I first saw it in a prosthesis machine shop at a rehab hospital.

RE: Cyclobe.
Wood dust Cyclones use multi circular operation to separate dust from air.
That drum is just a half circle separator because steel is about 7.5 -15 denser than wood so half a circle e use enough.

Originally Posted by Kristen

Not sure if it helps but it's about 375H x 410W.

The impeller is removed by taking off the cover plate that the inlet attaches to, so it’s smaller that that plate, by the amount of space taken up by the screws.